<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div id="app">
        <span v-if="show">
            {{ str1 }}
        </span>
        <span v-else>
            {{ str2 }}
        </span>
    </div>

    <script src="https://unpkg.com/vue/dist/vue.js"></script>
    <script>
        let app = new Vue({
            el: '#app',
            data() {
                return {
                    show: true,
                    str1: '窝叫一个林',
                    str2: '林叫一个窝'
                }
            }
        })
    </script>
</body>

</html>